The present invention relates to fuse cutouts that can be used with power distribution systems to protect against electrical overload. In particular, the fuse cutout includes a mounting assembly, a pivotally movable fuseholder assembly received in the mounting assembly, a fuse link held within the fuseholder, and an integrated lever that serves both as a link ejector and a link break lever.
The primary purpose of a fuse cutout is to protect power distribution systems and the various apparatus on those power lines such as transformers and capacitor banks. An over current or electrical overload in the system can occur under various conditions, such as an animal or tree contacting the power lines or more than one power line contacting each other. The fuse cutout acts to interrupt the current, and then the fuseholder of the cutout xe2x80x9cdropsxe2x80x9d, thereby preventing the voltage from being impressed across the fuseholder and providing a visual indication of operation to the utility line crew. Specifically, upon occurrence of an overload, the fuse link disposed within the fuseholder melts allowing the fuseholder to drop and interrupt the current.
Conventional cutouts typically include a mechanism for ejecting the fuse link once it has melted to avoid damage to the fuseholder. The link ejector usually comprises a spring biased member that biases the fuse link out of the fuseholder. In addition, some conventional cutouts employ a lever separate from the link ejector for manually breaking the fuse link when desired. The lever includes an outwardly extending lever arm that can be pulled down to mechanically break the fuse element.
The use of two separate members for ejecting the link and for manually breaking the link increases costs in manufacturing the cutout. Moreover, installation of the fuse link is difficult since the link must first be woven through the lever, then the lever must be pivoted away and clear from the link, and finally the link can be extended under and across the link ejector. In addition, the pressure applied due to the biasing force of the link ejector plus the mass of the link ejector and the link break lever in present designs, may cause some smaller diameter fuse links to prematurely break.
Another problem with conventional fuse cutouts is the failure to provide a mechanism for ensuring the proper installation of the fuse element. As a consequence, the fuse link could be too lose such that the fuseholder begins to drop-out just prior to the fuse link melting upon the occurrence of an overload, resulting in flashover arcing and catastrophic failure of the cutout.
Other problems with the conventional fuse cutouts are that the prior link ejectors require both the weight of the fuseholder plus the force of a top contact spring on the fuseholder in addition to the biasing force of the link ejector, to properly and efficiently eject the link during each drop out of the fuseholder. Moreover, their link break levers are too bulky and their position with respect to the fuseholder obstructs the use of tools, such as a hot stick, when attempting to manually operate the fuseholder.
Examples of such conventional fuse cutouts are disclosed in the following U.S. Pat. No.: 2,230,955 to Johnson; U.S. Pat. No. 2,269,372 to Johnson; U.S. Pat. No. 2,310,466 to Schultz et al.; U.S. Pat. No. 2,458,742 to Schultz; U.S. Pat. No. 2,584,586 to Hubbard; U.S. Pat. No. 2,862,080 to Yonkers; U.S. Pat. No. 2,910,560 to Stroup et al.; U.S. Pat. No. 3,827,010 to Cameron et al.; U.S. Pat. No. 4,542,363 to Kato et al.; U.S. Pat. No. 4,546,341 to McNaghten et al.; U.S. Pat. No. 4,774,488 to Field; and U.S. Pat. No. 4,857,879 to Morgan.
Accordingly, an object of the present invention is to provide a fuse cutout that integrates the functions of a link ejector and a link break lever into one unitary or one-piece member.
Another object of the present invention is to provide a fuse cutout that includes an integrated link break lever that reduces manufacturing costs and increasing efficiency in operating the cutout.
A further object of the present invention is to provide a fuse cutout with an integrated link break lever having a reduced mass that limits the mechanical strain on the fuse link.
Yet another object of the present invention is to provide a fuse cutout with an integrated link break lever that facilitates and ensures proper installation of the link lever, by even relatively inexperienced lineman.
A yet further object of the present invention is to provide a fuse cutout with an integrated link break lever that is unobtrusive and does not interfere with the operation of the fuseholder.
A still yet further object of the present invention is to provide a fuse cutout with an integrated link break lever that consistently ejects the fuse link upon occurrence of an overload and drop out of the fuseholder.
The foregoing objects are basically attained by a fuse cutout for connection to a power source, comprising a mounting having upper and lower support members extending from opposing ends of the mounting, respectively. A holder member is fixedly attached to the lower support member of the mounting. A pivot member is received in the holder member, the pivot member being movable between first and second positions. A lever member is movable between non-release and release positions, and has unitary first and second portions The first portion is pivotally coupled to the pivot member at the first pivot point. A fuseholder is movable between closed and open positions, and has upper and lower ends. The lower end is pivotally coupled to the pivot member at a second pivot point. A central axis extends along a length of the fuseholder. Each of the first and second positions of the pivot member and each of the closed and open positions of the fuseholder correspond to each of the non-release and release positions of the lever member, respectively.
The foregoing objects are also attained by a fuse cutout for connection to a power source, comprising a mounting having upper and lower support members extending from opposing ends of the mounting, respectively. A holder member is fixedly attached to the lower support member of the mounting. A pivot member is received in the holder member, with the pivot member being movable between first and second positions. A lever member is movable between non-release and release positions, and has unitary first and second portions and a first engaging element. The first portion is pivotally coupled to the pivot member at the first pivot point. A fuseholder is movable between closed and open positions, and has upper and lower ends. The lower end is pivotally coupled to the pivot member at a second pivot point. A central axis extends along a length of the fuseholder. A second engaging element corresponds to the first engaging element. The second portion of the lever member extends beyond the outer periphery of the fuseholder. Each of the first and second positions of the pivot member and each of the closed and open positions of the fuseholder correspond to each of the non-release and release positions of the lever member, respectively. The first and second engaging elements are engaged when the lever member and the fuseholder are in the non-release and the closed positions, respectively.
By designing the fuse cutout in this manner, the cost of manufacturing the cutout is reduced and the efficiency in using the cutout is increased. In addition, installation of the fuse link is simplified. The integrated link lever also reduces strain on the fuse link and provides consistent ejection of the fuse link upon occurrence of an overload and drop out of the fuseholder.
Other objects, advantages and salient features of the invention will become apparent from the following detailed description which taken in conjunction with annexed drawings, discloses the preferred embodiments of the present invention.